Other's have mentioned that Forth isn't an esoteric language, however if you want a Forth written for an esoteric language I have written one for SUBLEQ (see https://esolangs.org/wiki/Subleq). Although SUBLEQ is more of an esoteric machine than a language, it also sort of qualifies as one (and has an entry on the esolangs Wiki).

It's available at https://howerj.github.io/subleq.htm if you want to try it online.